Mars and Craters: Gale and Eberswalde Craters and More Information

As New Horizons has been hauling in fascinating photos and insights about Pluto and Mars lately, here's a quick update on two of the craters on Mars.

Gale Crater has a mountain at its center that would be three miles high on Earth. It layers materials, letting us know some of its planetary history. The layers have various minerals depending on their height--with clay minerals near the bottom. On top of those are sulfur, then minerals containing oxygen. It seems that flowing water made channels in the mountain and the Gale Crater wall. These findings have been made from orbit studies, but the Mars Science Laboratory could land in the crater's flattest areas and work its way upward in order to see everything up close.

Eberswalde Crater is an ancient river delta, and provides convincing evidence that a river once flowed on Mars into standing water. Over time the delta's stream channels have moved and carved new routes, leaving behind abandoned streambeds. Those beds are now at a higher grade than the surrounding land, because water left behind sediments, which solidified and resisted erosion. Orbiters have picked up on clay in the sediments--these show that there was past water activity, which the Mars Science Laboratory will likely investigate. How clay forms: water breaks down rocks into much finer minerals. The minerals then form layers.